Question

Explain the ways in which aerobic respiration and fermentation processes are different. Name the three phases of aerobic respiration and give the starting materials and end products of each phase. Describe a difference in the glycolysis pathways of bacteria and eukaryotic microorganisms. Describe how a bacterium uses an electrochemical gradient to generate ATP.

Answer 1

Ans) In Aerobic respiration CO2, water and energy in the form of ATP is produced in the presence of oxygen whereas fermentation is a process of energy production in the absence of oxygen. Aerobic respiration occurs in cytoplasm and mitochondria whereas fermentation occurs only in cytoplasm.

The three phases of aerobic respiration are:-

1) Electron transport chain (ETC):-  

Start product of ETC:- NADH

End product:- water and ATP.

2) Kreb's cycle:-

Start product of kreb's cycle:- acetyl CoA and oxaloacetate.

End product:- oxaloacetic acid.

3) Glycolysis:-

Start product:- glucose

End product :- pyruvate.

A major difference between glycolysis pathway of bacteria and eukaryotes is that, in eukaryotic cell post-glycolytic reactions take place in mitochondria whereas the same takes place for bacteria in cytoplasm.

The gradient is usually used to drive ATP synthase, flagellar rotation and transport of metabolites. It also focuses on three processes important to estabilish proton gradients:- bacteriorhodopsin, noncyclic photophosphorylation and oxidative phosohorylation.